Tinsel wire connector



Nov. 9, 194s. M. D. BERGAN 2,453,615

TINSEL WIRE CONNECTOR Filed Aug. 10, 1946 @i f AIII-Illllllll'l llllllllllllm Aira/PMS? Pumas Nov. 9, 1914s 2,453,615 i l maar. wmaooNNac'ron Manin n. nemnv,

orte

The Thomas & Betts Co., Ellnbe J., l.`

clinici-ation of'New Jersey Application August 1o, 194s, serial Nn.

2 claim. (ci. 173-269) The invention relatesv to a terminal for anelectric cable, cord 'or conductor and the invention specificallyrelates to 'an electric terminal connector, lug or clipfor .use withcables, cord plugs, or similar electric conductors having a conductor ofthe multiple strand wire type encased in an insulation of any one of theusual types.

In one form of such cables or conductors now in general use, commonlycalled tinsel wire conductors, the core is made up of a bundle of ilnewires enclosed in an insulation which is made up of cotton or silkthreads wound spirally on Vthe wire core. This form of insulation doesnot permit of the usual -practice of stripping or cutting back an end oithe insulation so as to provide an exposed end of the conductor forconnection with the terminal. In thisart it has been suggested toprovide terminals with inturned prongs which bite through the insulationlaterally to make a more or less haphazard contact through the sides ofthe wire core conductor. An obvious objection to this transversepunchingxprocedure is that the prong might not contact the conductor atall, and even if it did the contacting area between the pointed end ofthe prong and the side of the conductor is limited to the inevitablysmall area which makes up the extreme pointed end of the prong. In suchcases the contacting area bef tween the pointed end `or sides of theprongs and the wires are too small and too casual.

The primary object of the invention is to provide a simple, one-pieceform of terminal, re-

seam

, 2 this might possibly tend m especially if it happened to be quitethin orshould there by any bending back and forth :between the cable andterminal while in use. In order to avoid this` possibility the presentdisclosure ieatures a ferrule or clip which will perform the dualfunction of restraining any outward distortion of the insulation in thepar-t thereof which contains the connecting prong and `at thesame timeto insure a' positive compression of the bundle of wires about the prongand also to protect and armour the end of the insulation and thus f tovdefeat the possibility of its ravelling.

sembling conventional forms of such terminals in that it may be formed'as a simple stamping operation and which will positively insure anextensive area of contact between the terminal and the wire conductorwhen installed in position on the cable by the simple act of pushing thecable and terminal together endwise.

Broadly, this aspect of the disclosure is attained by providing theterminal with a pin-like prong of any desired length arranged to enterinto and to extend lengthwise of and embedded in the bundle of wiresforming the conductor or core to extend in the direction lengthwise ofthe core rather than at right angles to the length of the core asin theprior art.

In this way there is avoided any necessity of stripping back or in anyother way modifying the insulation and the insulation being thusretained n intact insures the retention of the entire cable insulationup to the exposed prong or blade of the terminal.

The .intrusion of the prong into the bundle of wirse of course tends tospread the bundle and Various other objects and advantages-of theinvention will be in part obvious from an inspection of the accompanyingdrawings and in part will be more fully set forth in the following par-4ticular description of one form of device embodying the invention. andthe invention also consists in certain new and novel features'ofconstruction and combination of .parts hereinafter set forth w..

and claimed.

In the accompanying drawings:

Fig. 1 is a view partly in side elevation vand partly in verticalsection of a terminal, very much enlarged, forming a preferredembodiment of the invention and showing one of a pair of.; blades of amale connecting plug for insertion into an electric outlet receptacle; i

Fig. 2 is a transverse sectional view taken on the line 2-2 of Fl. l;

Fig. 3 is a plan view of the stamped blank from which the terminals ofthe other views are formed? Fig. e is a composite view in plan of theterminal shown in Fig. 1 with an end ofthe cable located in position tobe inserted therein when moved in the direction of the arrow;

Fig. 5 is a view in side elevation of the showing of Fig. 4; and

Fig. 6 ls a transverse sectional view taken on the line 6-6 of Fig. 5looking in the direction indicated by the arrows.

In the drawings and referring ilrst to Fig. 1, the terminal-hereinfeatured is intended to conduct current to or from a cable of the typewhich has a spirally wound insulation E encasing a bundle of fine wiresat its core forming a conductor G.

The terminal is formed from a blank i0 as shown in Fig. 3 and whichcomprises a strip of thin bendable sheet metal punched to shape as islusual with similar forms of terminal blanks.

The strip I0 is recessed at opposite sides adjacent its mid-length toform a portion reduced in width and adapted to be bent back sharply uponitself to rupture the insulation i along the transverse axis of bend a-bmid-length of this reduced portion. The blank strip is provided inspaced relation to the axis w-b and on opposite sides thereof with apair of apertures I2 and I3, One end of the strip is of increased widthto form a wide, rectangular, clipor tube forming head Il. This head isprovided on the side which is to become the inner side of the nnishedterminal with serrations Il or is otherwise provided witha roughenedfacing.

The end of the strip opposite to the head is provided with a long, sharppointed prong II extending axially of the strip and dlmensioned in widthso as to be intruded axially into the bundlel of wires forming theconductor G. Preferably the prong is of the wide-shape or reversetapered form -shoWn to obtain a greater resistance to the conductorpulling oil' of the prong than would be the case if the prong was ofuniform width in rear of its pointed end.

'I'he ilat strip blank IB is bent back upon itself across the axis a-bto form a smooth turn I1 as viewed in Fig. and' a bevelled endnose inplan as shown in Fig. 4. The `bent .portions are forced firmly one on tothe other. When so bent there is formed a ytongue or blade of doublethickness of material which tends to give the necessary rigidity to theblade portion of the terminal, even when formed of thin stock material.The blade portion is thus formed with a long flat upper length I8, withthe prong I5 in the plane thereof and a longer lower length I9. Theblank is so folded that the apertures I2 and I3 are brought intoregistry to form the usual holding hole 20 found in such devices. i

Ihe parts are so proportioned that when so bent the head I4 underlapsprong I6 and opposite sides of the head are rolled inwardly towards eachother by the action of a suitable die press to form the U-shaped orsplit sleeve 2 I. The sleeve is formedV concentric with the prong IB andi-ts inner face is in radially spaced relation to the prong as shown inFig. 6 to receive the entire end of the cable. i

lit is-suggested that the inner end of the bore of the sleeve be ofslightly greater diameter than the outer end as shown in Fig. 4 tocompensate` for the greater width of the prong at its root end than atits pointed end. In order to bring the prong into the axis of theconductor the split sleeve is offset from the plane of the length I9 radistance equal to the radial lthickness of the insulation E and thisforms a Z-bend 22 at the point where the sleeve 2| joins the lowerlength I9 of the tongue forming portion of the terminal.

It is understood that the terminals are supplied to the operator asshown to the left oi' Figs. 4 and 5 and lthat size terminal is selectedby the operator which is designed for use with the particular size ofcable for which it is intended. The operator prepares the cable bycutting off the end squarely as shown to the right of Figs. 4 and 5. Inassembling the cable end so prepared and the terminal they are relatedin axial alignment as shown in Figs. 4 and 5 and the squared oil end ofthe cable is simply' inserted axially into the open end of the splitsleeve as indicated by the arrows.` As the prong I6 moves into thebundle 4 of wires it embeds itself therein incidentally tending tospread the wires about the same as shown in Fig. 1. This tendency tospread is resisted b! cable has been inserted therein or to crimp orindent the sleeve into a more secure binding engagement with theinsulation.

Should it be desired to remove the terminal from the cable it is simplynecessary to forcibly pull them apart and which leaves them andparticularly the terminal available for subsequent use.

n I claim: i l An article oi' manufacture constituting an electricalterminal for attachment to an insulated cable having a conductor core,said terminal formed of one piece of sheet metal bent back upon itselfto form two superposed sections, the free end of one of said sectionsterminating in a split sleeve of cylindrical form dimensioned to receivethe cable with a sliding fit when inserted therein.'

and the free end of the other section terminating in a prong, the prongbeing centered in the sleeve` and extending along the axis of thesleeve, said terminal being so preformed to shapeand ready to receivethe cable when inserted into the split sleeve and said prong located topenetrate into the conductor core when the cable is inserted into thesleeve.

2. A preformed article 'of manufacture constituting an electricalterminal for attachment to an insulated cable having a conductor core,said terminal formed of one piece of sheet metal bent back upon itselfto form two superposed sections in-rm flatwise abutting relation to forma tongue of a double thickness of material at one Aend of the terminal,the free end o! one section terminating in a. sleeve open at oppositeends, Vthe free end of the other section terminating in a prongextending axially into the sleeve, said sleeve being axially offset fromthe tongue and providing at the point where the sleeve joins with thetongue a Z-bend to form a stop for limiting the insertion of the cableinto the sleeve end of the prong into the conductor core.

l MARTIN D. BERGAN.

REFERENCES CITED The following references are of record in the tile ofthis patent:

UNITED STATES PATENTS 596,406 France Aug. s, 1925

